Detcon FP-624C User Manual

Page 17

First, enter the programming menu by holding the programming magnet stationary over “PGM 2” for 30 sec-

onds until the display reads

“VIEW PROG STATUS”, then withdraw the magnet.

Next, scroll to the

“SET CAL FACTOR” listing and then hold the programming magnet over “PGM 1” for 3

seconds. The menu item appears as

“CAL FACTOR #.##”. Use the programming magnet to make an adjust-

ment to “PGM 1” to increase or “PGM 2” to decrease the display reading until the reading is equal to the

desired K factor. Save value by holding the programming magnet over “PGM1” for 3 seconds.

Exit back to normal operations by holding the programming magnet over “PGM 2” for 3 seconds, or automati-

cally return to normal operation in 30 seconds.

3.8 C

ALIBRATION

Material Requirements

Detcon PN 3270 MicroSafe™ Programming Magnet

Detcon PN 6132 Threaded Calibration Adapter

Span Gas containing the applicable calibration gas in air (see section 3.7). Span gas concentration is recom-

mended at 50% of range (which is the factory default) at a controlled f low rate of 200 ml/min. Other concen-

trations can be used as long as they fall within 10% to 90% of range. See section 3.8.2 for details.

3.8.1 Calibration Procedure - Zero

NOTE: Before performing a zero calibration, be sure there is no background target gas present.

Enter the calibration menu by holding the programming magnet stationary over “PGM 1” (see figure 7) for 3 sec-

onds until the display reads

“1-ZERO 2-SPAN”, then withdraw the magnet. Note that the “CAL” LED is on.

Next, enter the zero menu by holding the magnet stationary over “PGM 1” for 3 seconds until the display

reads:

“ZERO 0%”, then withdraw the magnet. The sensor has now entered the auto zero mode. When it is

complete the display will read

“ZERO COMPLETE” for 5 seconds and then return to the normal operations

menu,

“0 % LEL”.

NOTE 1: If the circuitry is unable to adjust the zero to the proper setting the sensor will enter a calibration

fault mode which will cause the display to alternate between the sensor’s current status reading and the calibra-

tion fault screen which appears as:

“CAL FAULT” (see section 3.8.3).

NOTE 2: In every instance where a sensor is re-zeroed, the zero error is directly proportional to resulting span

error. For example, if a sensor zero error is 2 %, upon completion of auto zero, the resulting span error is 2 %.

When this error exceeds 5% of full scale sensitivity, the sensor should be calibrated with span gas.

NOTE 3: When a “cal fault” occurs, the sensor microprocessor retains its previous calibration references.

Zero calibration is complete.

3.8.2 Calibration Procedure - Span

CAUTION: Verif ication of the correct calibration gas level setting and calibration span gas concentration is

required before “span” calibration. These two numbers must be equal.

Calibration consists of entering the calibration function and following the menu-displayed instructions. The display

will ask for the application of span gas in a specif ic concentration. This concentration is equal to the calibration gas

level setting. The factory default setting for span gas concentration is 50% LEL. In this instance, a span gas contain-

ing a concentration equal to 50% LEL is required. If a span gas containing 50% LEL is not available, other concen-

trations may be used as long as they fall within 10% to 90% of range. However, any alternate span gas concentra-

tion value must be programmed via the calibration gas level menu before proceeding with span calibration. Follow

the instructions below for span calibration.

Model FP-624C Combustible Gas Sensor PG.17